Method of continuously plating a steel strap on one surface

ABSTRACT

THIS INVENTION RELATES TO A NOVEL ONE-SURFACE CONTINUOUSLY ELECTROPLATING METHOD FOR CONTINUOUSLY APPLYING AN ELECTROPLATING FILM TO ONE SURFACE OF A COMPARATIVELY THIN STEEL STRAP.

1972 MASAYOSHI USU] 3,697,399

METHOD OF CONTINUOUSLY PLATING A STEEL STRAP ON ONE SURFACE Filed June 5, 1971 v 5 Sheets-Sheet 1 Oct. 10, 1972 MASAYOSHI USU] 3,697,399

METHOD OF CONTINUOUSLY PLATING A STEEL STRAP 'ON ONE SURFACE Filed June 5, 1971 3 Sheet-Sheet 2 I II II/ A/ 1 [11 I1 I 1 MASAYOSHI usul 3,697,399

METHOD OF CONTINUOUSLY PLATING A STEEL STRAP ON ONE SURFACE Filed June 3, 1971 3 Sheets-Sheet 3 United States Patent 6' U.S. Cl. 204-15 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a novel one-surface continuously electroplating method for continuously applying an electroplating film to one surface of a comparatively thin steel strap.

In making a pipe by winding a thin steel strap, there is a case wherein the steel strap need not be plated on both surfaces. For example, as a conventional double-wound steel pipe obtained by winding a thin steel strap copperplated on both surfaces is coated with copper on both inside and outside surfaces of the pipe, a melt-coating with zinc applied to its outer peripheral surface is so likely to peel off under the influence of the copper-plating film when the pipe is bent that no coating layer is obtained which is as good in bonding as a zinc melt-coating applied directly to the surface of a steel material. Further, if an electroseamed pipe copper-plated on the inside surface is made by using a thin steel strap copper-plated on both surfaces, a brittle layer is produced in the seam and a tough pipe is not obtained.

Such problem is solved with a double-wound steel pipe having a steel skin on the outside surface. The method of the present invention has made it possible to very efficiently produce a steel strap plated on one surface and, indispensable to the production of such double-wound steel pipe, having a steel skin on its outside surface.

This invention relates to a novel one-surface continuously electroplating method for continuously applying an electroplating film to one surface of a comparatively thin steel strap.

In making a pipe by winding a thin steel strap, there is a case wherein the steel strap need not be plated on both surfaces. For example, as a conventional double-wound steel pipe obtained by winding a thin steel strap copperplated on both surfaces is coated with copper on both inside and outside surfaces of the pipe, a melt-coating with zinc applied to its outer peripheral surface is so likely to peel oif under the influence of the copper-plating film when the pipe is bent that no coating layer is obtained which is as good in bonding as in a zinc melt-coating applied directly to the surface of a steel material. Further, if an electroseamed pipe copper-plated on the inside surface is made by using a thin steel strap cooper-plated on both surfaces, a brittle layer is produced in the seam and a tough pipe is not obtained.

The inventor has made the present invention aiming at that the above mentioned various problems can be solved by using a steel strap plated on one surface. In other words, the present invention has been made with a view to provide a method of efliciently making the steel strap plated on one surface so as to solve the various above mentioned problems.

The subject matter of the present invention is to provide a method of continuously electroplating a steel strap on one surface by passing the steel strap attracted and coated with a flexible band-shaped sheet magnet on one Patented Oct. 10, 1972 ice surface through an electroplating tank and then peeling off the band-shaped sheet magnet.

The present invention shall be explained with reference to the accompanying drawings, that is, as follows;

In the drawings:

FIG. 1 is a view of an electroplating process consisting of a main part according to the present invention and attached parts;

FIG. 2 is a magnified sectioned view on line IIII in FIG. 1;

FIG. 3 is a magnified sectioned view on line III-III in FIG. 1;

FIG. 4 is a magnified sectioned view on line IV-IV in FIG. 1;

FIG. 5 is a magnified sectioned view on line VV in FIG. 1;

FIG. 6 is a schematic view showing another embodiment of the main part;

FIG. 7 is a magnified sectioned view on line VII-VII in FIG. 6;

FIG. 8 is a partly cut-away schematic view showing still another embodiment of the present invention. The crosssectional view on line VIIIVIII in FIG. 8 appears the same as in the above mentioned FIG. 3, therefore the view on line VIIIVIII is omitted;

FIG. 9 is a schematic plan view of FIG. 8;

FIG. 10 is a partly cut-away schematic view showing still another embodiment of the present invention. The cross-sectional view on line X-X in FIG. 10 appears the same as in the above mentioned FIG. 3, therefore the view on line X-X is omitted;

FIG. 11 is a schematic plan view of FIG. 10.

The present invention shall be explained in detail with reference to FIG. 1. 1 is an uncoiler for a steel strap 2 which has been struck in advance or not, 2a is a steel strap electroplated P on one surface and each of 2 and 2a may be merely called a steel strap hereinafter. A general cleaning device 3 consists of a defatting tank, de- Iusting tank and dryer. The reference 4 denotes a flexible band-shaped sheet magnet (which shall be merely called a band-shaped sheet magnet). The reference 5 denotes a device for attracting and coating the steel strap with the band-shaped sheet magnet and consisting of 5a, 5b and 5c. The reference 5a denotes an uncoiler for the bandshaped sheet magnet 4, and 5b and reference 5c denote lapping rolls for guiding one surface of the band-shaped sheet magnet 4 to attract one surface of the steel strap 2. The reference 6 denotes a path through which the steel strap attracted by the band-shaped sheet magnet 4 goes from the inlet side to the outlet side of an electroplating tank and references 6a, 6b, 6c and 6d denote guide rollers arranged and set in the path 6 to lead the steel strap 2 attracted by the band-shaped sheet magnet 4 into the electroplating tank and pass it through the tank. The rollers 6a and 6d are also cathodes. The reference 7 denotes an electroplating tank. The reference 7a denotes an electroplating solution. The reference 7b denotes an electric copper anode. The reference 8 denotes a washing and drying device. The reference 9 denotes a peeling device to peel the band-shaped sheet range 4 oif the steel strap 2a electroplated on one surface and consists of 9a, 9b and 9c. The reference 9a denotes a recoiler for the bandshaped sheet magnet 4. The references 9b and 9c denote rollers for peeling off the band-shaped sheet magnet 4. The band-shaped sheet magnet 4 peeled off the steel strap 2a is led to the recoiler 9a. The reference 10 denotes a recoiler for recoiling the steel strap 2a electroplated on one surface. In each drawing, the arrow indicates the direction in which the corresponding part runs or rotates and the wirings of both cathodes 6a and 6d and the anode 7b are omitted. The above process in which the steel strap 2 passes from the lapping device 5 to the peeling device 9 through the electroplating tank 7 is in the main part of the present invention. In the process, the steel strap 2 having the cross-section illustrated in FIG. 2 is attracted and coated with the band-shaped sheet magnet on one surface as illustrated in FIG. 3, passes through the electroplating tank 7 so as to be electroplated only on one surface as illustrated in FIG. 4 but not to be electroplated on the surface attracted and coated with the band-shaped sheet magnet 4 and then passes through the peeling device 9 so that the one-surface electroplated steel strap 21: illustrated inFIG. 5 may be peeled off the bandshaped sheet magnet 4.

As well known, the band-shaped sheet magnet 4 to be used in the method of the present invention is obtained by mixing and kneading a magnetizable powder with a thermoplastic synthetic resin, extruding it with a die and magnetizing it. The magnetizable powder may be a known powder of any special steel or barium ferrite. It is preferable that the attracting surface of the band-shaped sheet magnet 4 be smooth. Therefore, any rough surface of such sheet magnet to be used may be made smooth by being fused and coated with soft resin. When the sheet magnet with a rough surface as is to be used, a tape which is nonpenetrable by the electroplating solution (and which shall be merely called a nonpenetrable tape hereinafter.) may be inserted between the steel strap 2 and the bandshaped sheet magnet 4 in passing them through the electroplating tank. The tape used in such case is selected from such magnetically permeable material as a thin plate made of a soft synthetic resin or thin kraft paper.

FIG. 6 shows an example of working the present invention by preventing the penetration by the liquid when the attracting surface of the band-shaped sheet magnet 4 is rough. That'is to say, in FIG. 6, 11 denotes a nonpenetrable tape and 12 a tape introducing device consisting of 12a, 12b and 120 so that the nonpenetrable tape 11 may be led by this device between the contact surfaces of the steel strap 2 and band-shaped sheet magnet 4. The reference 12a denotes an uncoiler for the tape 11. References 12a and 120 denote guide rollers for the tape 11. The reference 13 denotes a nonpenetrable tape peeling device consisting of parts 13a, 13b and 130. The reference 13a denotes a recoiler for the nonpenetrable tape 11. References 13b and 130 are guide rollers. The references 5, 8 and 9 denote, respectively, the same as the corresponding parts in 'FIG. 1. As the. process parts illustrated in FIG. 6 are formed as mentioned above, the steel strap 2 having passed through the nonpenetrable tape introducing device 12 and the band-shaped sheet magnet lapping device 5 attracts the band-shaped sheet magnet 4 throughthe nonpenetrable tape 11 on one surface as illustrated in FIG. 7 and passes through the electroplating tank 7. In such case, as the nonpenetrable tape 11 is inserted, even if the surface of the band-shaped sheet magnet 4 is rough, no electroplating solution 7a penetrates it and therefore the steel strap electroplated only on one surface passes through the electroplating tank 7, washing dryer 8 and peeling devices 9 and 13 so that a steel strap 2a electroplated P on one surface the same as in FIG. 5 may be obtained.

By the way, in the above, the case of attracting the steel strap to one surface of the band-shaped sheet magnet 4 has been described. However, it is needless to say that such steel strap may be attracted to each surface of the band-shaped sheet magnet.

Further, it is thought that, in the method of the present invention, a long band-shaped sheet magnet 4 is necessary. But, if an electroplating apparatus consisting of the structure illustrated in FIG. 8 is used, the band-shaped sheet magnet to be used can be saved. That is to say, in FIG. 8, reference 4 denotes an endless sheet magnet rotatably provided as partly dipped in an electroplating solution. Said endless sheet magnet rotates to form an upper part 4a, inlet side part 4b,"lower part 40 and outlet side part 4d and the attracting surfaces of the parts in the electroplating solution are arranged in the path of the steel strap 2 in the tank. Reference 6 denotes a group of rollers provided in the rotating path of the endless sheet magnet 4 and consists of rollers 6a, 6b, 6c, 6d, 6e and 6f. References '6b, 6e, 6e and 6 denote guide rollers to guide the endless sheet magnet 4 in its rotating path. Reference 6a denotes a guide roller on the inlet side and forms an inlet 2b for the steel strap 2 coming running toward the electroplating tank 7 near the inlet side part 4b outslde the solution. Reference 6d denotes a guide roller on the outlet side and forms an outlet 20 for the steel strap 2 coming through the tank near the outlet side part 4d.

As the electroplating apparatus illustrated in FIG. 8 is thus formed, the steel strap 2 has its one surface attracted to the endless sheet. magnet 4 at the inlet 2b, is led into the electroplating solution by being guided by the guide rollers 6a, 6b, 6c and 6d, comes out through the outlet 20 and is peeled off the endless sheet magnet 4. On the other hand, the endless sheet magnet 4 advances toward the inlet side and the steel strap 2a electroplated on one surface is wound up by the recoiler 10. Further,

reference 4e denotes an electroplating solution removing device provided to remove the electroplating solution deposited on each side of the endless sheet magnet 4 coming as peeled off the steel strap 2a and properly designed to be used. As both inlet 2b and outlet 20 are provided above the electroplating solution 7a, in case the steel strap 2 is attracted by the endless sheet magnet, 4 at the inlet 2b, the electroplating solution does not penetrate between them and the steel strap 2 as attracted to the surface of the endless sheet magnet 4 advances into the electroplating solution. Therefore, the surface of the endless sheet magnet 4 having had the steel strap 2a peeled off at the outlet 20 is not wet with the solution. As it is preferable that the width ofthe endless sheet magnet 4 is made somewhat larger than the width of the steel strap in the embodiment, the attracting surface of the endless sheet magnet cannot help being wet with the solution on both sides. Such part wet with the solution it isnot desirable to the steel strap to be attracted again, but being so small it is easily dried even during the rotation of the endless sheet magnet 4. For example, as illustrated, by blowing air, it can be effectively dried.

The purpose of the deposited solution removing device 4e shown in FIGS. 8 and 9 is to remove the deposited solution by blowing air. The broken lines in the drawings show blowing of air.

Thus, the electroplating path formed by the endless sheet magnet 4 is U-shaped in FIGS. 8 and 9, butis formed to be horizontal in FIGS. 10 and 11.

The apparatus shown in FIGS. 10 and 11 shall be explained. Therein, reference 7 is an electroplating tank consisting of parts 7.1, 7.2, 7.3, 7.4 and 7.5. Reference 7.1 denotes an outer tank. Reference 7.2 denotes an inner tank, 7.3 reference denotes an inlet side cover. Reference 7.4 denotes an outlet side cover, reference 7.3a denotes 'a horizontal slot made on the inlet side surface of the cover 7.3, references 7.2a and 7.2b denote horizontal slots made respectively on the inlet side and outlet side of the inner tank 7.2, reference 7.4b denotes a slot made on the outlet side surface of the cover 7.4. These slots are made to be connected in the same plane so that the steel strap 2 attracted to the lower part 40 of the endless sheet magnet may be led to pass horizontally linearly through the electroplating solution from outside the tank. Reference 7.5 denotes an electroplating solution circulating pump which draws the electroplating solution from the outer tank 7.1 to the inner tank 7.2. The drawn electroplating solution returns to the outer tank through the horizontal slots 7.2a and 7.2b of the inner tank and thus circulates through the inner and outer tanks. In the drawings, reference 6 denotes a group of rollers provided in the rotating path of the endless sheet magnet 4 and consists of rollers 6a, 6b, 6c, 6d, 6e and 6}. The rollers 6b, 6c, 6e and 6 guide the endless sheet magnet 4 so as to rotate through the horizontal electroplating path in the inner tank 7.2. Reference 6a denotes a guide roller on the inlet side and forms an inlet 2b for the steel strap 2 by approaching from below the horizontal part of the lower part 40 of the endless sheet magnet 4 outside the solution. Reference 6d denotes a guide roller on the outlet side and forms an outlet 20 for the steel strap by approaching from below the horizontal part of the lower part 40 of the endless sheet magnet 4 outside the solution. According to the apparatus in FIGS. 10' and 11, the method of the present invention can be worked by horizontally linearly introducing and running the steel strap through the electroplating solution.

EXAMPLE 1 Apparatus In the process view illustrated in FIG. 1, three electroplating tanks 7 are arranged in series and the distance between the guide rollers 6b and 6c and the rising depth from the rollers up to the solution surface in each electroplating tank are adjusted to be respectively 4 meters and 1 meter.

The steel strap to be used is struck on the surface to be plated and is so clean that no cleaning device need be used.

Raw materials The band-shaped sheet magnet 4 is smooth on the surface and has a contact attraction of 40 g./cm. width of 80 mm., thickness of 2 mm. and length of 50 meters.

The steel strap 2 is of soft steel, width of 70 mm., thickness of 0.35 mm. and length of 100 meters and is struck for 1 minute on only one surface in the same manner as in the embodiment by using a pretreating solution of 140 g./l. of copper pyrophosphate, 120 g./l. of potassium pyrophosphate and 10 g./l. of potassium oxalate.

The electroplating solution 7a is of 340 g./l. of potassium pyrophosphate, 100 g. l. of copper pyrophosphate and 2 g./l. of ammonia and pH of the solution was 8.8.

The anode material 7b is electric copper.

The cathodes are the guide rollers 6a and 6d.

Operation The struck clean steel strap 2 was passed through the lapping device to be attracted on the surface not struck by the band-shaped sheet magnet 4, is passed through the three electroplating tanks arranged in series and holding the electroplating solution at a temperature of 55 C. at a current density of about 4 amperes/dm. and velocity of about 4.5 meters/ minute, is passed through the device 8 to be Washed and dried, is then passed through the peeling device 9 to have the band-shaped sheet magnet 4 peeled off and wound up on the recoiler 9a and is wound up on the recoiler 10 to be a one-surface electroplated steel strap 2a having a copper-plating layer of a thickness of about 6,u. formed on one surface. In this example, the steel strap 2a is pulled on the recoiler side.

EXAMPLE 2 Apparatus The apparatus is the same as in Example 1 except that the non-penetrable tape 11 introducing device 12 and peeling device 13 are attached.

Raw materials The band-shaped sheet magnet 4 is rough on the surface and has a contact attraction of 45 g./cm. width of 100 mm., thickness of 2 mm. and length of 50 meters.

The steel strap 2 is of soft steel, width of 90 mm., thickness of 0.58 mm. and length of 100 meters.

The nonpenetrable tape 11 is kraft paper of a thickness of about 0.1 mm.

The electroplating solution 7a is of 60 g./l. of copper cyanide, 9O g./l. of potassium cyanide and 10 g./l. of potassium hydroxide and a pH of 12.5.

The anode material 7b is electric copper.

The cathodes are guide rollers 6a and 6d.

Operation The cleaned steel strap 2 is passed through the nonpenetrable tape introducing device 12 and band-shaped sheet magnet lapping device 5 to have the band-shaped sheet magnet 4 attracted through the tape 11 on one surface, is passed in turn through the three electroplating tanks arranged in series at a current density of 25 amperes/dm. and velocity of 4.5 meters/minute, is passed through the device 8 to be washed and dried, is then passed through the peeling devices 9 and 13 to have the bandshaped sheet magnet 4 and nonpenetrable tape 11 wound up respectively on the recoiler 9a and 13a and is wound up on the recoiler 10 to be a one-surface electroplated steel strap 2a having a copper-plating layer of a thickness of about 5 formed on one surface. In this example, the steel strap 2a is pulled on the recoiler side.

EXAMPLE 3 Apparatus The apparatus is the same as in Example 1 except that the band-shaped sheet magnet lapping device 5 and peeling device 9 and the electroplating tanks 7 are replaced with the three electroplating tanks illustrated in FIG. 8.

Raw materials The endless sheet magnet 4 is smooth on the surface and had a contact attraction of 40 g./cm. width of mm., thickness of 2 mm. and endless length of 16 meters.

In FIG. 8, the distance between the rollers 6b and 6c is 4 meters, the rise from the rollers 6b and 6c up to the solution surface is 1 meter and the distance between the rollers 6f and 6e is 4 meters.

The steel strap 2, electroplating solution 7a, anode material 7b and cathodes are the same as in Example 2.

The cleaned steel strap 2 is passed in turn through the three electroplating tanks illustrated in FIG. 8 and arranged in series at a current density of about 25 amperes/ cm. and velocity of about 4.5 meters/minute, is then Water-washed and dried in the device 8 and is wound up on the recoiler 10 to be a one-surface electroplated steel strap 2a having a copper-plating layer of a thickness of about 5 formed on one surface.

In this example, the steel strap is pulled on the recoiler side and the endless sheet magnet 4 in each tank is rotated while attracting the steel strap running from the inlet 2b to the outlet 20. The electroplating solution is deposited on both side edges of the attracting surface of the endless sheet magnet 4 peeled oil? the steel strap 2a but is removed by blowing air with the devices 4e.

What is claimed is:

1. A method of continuously electroplating a steel strap on one surface comprising continuously passing the steel strap covered with a flexible band-shaped sheet magnet on one surface and left to be plated on the other surface through an electroplating tank and then peeling off said band-shaped sheet magnet.

2. A method of continuously electroplating a steel strap on one surface according to claim 1 wherein said flexible band-shaped sheet magnet is pulled out of an uncoiler, is applied to attract and cover the steel strap on one surface, is passed through the electroplating tank, is peeled off the steel strap and is the wound up on a recoiler.

3. A method of continuously electroplating a steel strap on one surface according to claim 1 wherein said flexible band-shaped sheet magnet is an endless sheet magnet rotating as partly dipped in the electroplating solution, is applied to attract and cover the steel strap on one surface when it enters the solution in the rotating step, is passed through the electroplating tank and is peeled off the steel strap.

4. A method of continuously electroplating a steel strap on one surface according to claim 1 wherein said flexible band-shaped sheet magnet is applied to attract the steel strap on one surface through a sheet nonpenetrable with electroplating solution.

5. A method of continuously electroplating a steel strap 3,274,092 9/ 1966 Marantz 204-224 on one surface according to claim 2 wherein said flexible 3,483,098 12/ 1969 Kramer 204-206 band-shaped sheet magnet is pulled out of the uncoiler 3,483,113 12/ 1969 Carter 204--28 and is applied toattract the steel strap on One surface 2,093,484 9/1937 Schlotter 204297 M through a tape nonpenetrable with the electroplating 5 2,047,418 7/ 1936 Kronsbein 204-297 M solution.

6. A method of continuously electroplating a steel strap FOREIGN PATENTS on one surface according to claim 3 wherein said endless 1,590,570 5/ 1970 France 204-297 M sheet magnet is rotated to attract the steel strap through a tape nonpenetrable with the electroplating solution. 10 JOHN MACK Primary Examiner T. TUFARIELLO, Assistant Examiner U.S. Cl. X.R.

References Cited UNITED STATES PATENTS 2,174,071 9/1939 Grupe 20428 3,178,305 4/1965 Ward 204l5 

